Students return to school in Greece as new Covid-19 measures take effect (video)
Some 56% of Greece's residents have been fully vaccinated
Data shows Covid booster shots are ‘not appropriate’ at this time, U.S. and international scientists conclude
They acknowledged that booster shots may eventually be needed for the general population if vaccine-induced immunity wanes even further
Pfizer CEO Albert Bourla says vaccine-resistant coronavirus variant would eventually emerge
Bourla added that Pfizer could produce new versions of its vaccine to combat a variant within three months of its discovery